The sleep apnea syndrome (SAS), more precisely the syndrome of obstructive apnea of sleep (SOAS) (as contrasted with the syndrome of central sleep apnea) is an affection generally caused by an obstruction of the respiratory tracts. It is susceptible to cause a certain number of disorders such as painful and insufficient breathing, heartbeat disturbance, and hypertension.
Various treatments of SOAS have been proposed including, for example, surgery, medications or maintenance of a positive pressure in the respiratory tracts by means of a facial mask applied during the sleep. It also has been proposed to treat SAS by neuro-muscular electric stimulation of the muscles controlling the air routes of the patient, as described in the U.S. Pat. No. 5,485,851 (to Medtronic, Inc.), and, more recently, by a particular stimulation of the myocardium (the so-called “electro-cardiac” stimulation) in the event of a detected SAS, as described, for example, in the U.S. Pat. No. 6,126,611 (to Medtronic, Inc.) and European patent application EO-A-0 970 713 and its corresponding U.S. Pat. No. 6,773,404. EP-A-0 970 713 (and U.S. Pat. No. 6,773,404) has the advantage of operating a discrimination between phases of awakening and sleep, in order to apply a therapy only during a phase of sleep, and to inhibit any treatment if the detected apnea occurs during a phase of awakening, because in this case it is normally not a pathological affection.